My PhD project aims to comprehensively investigate the theories, mechanisms and practices of (medical) vigilance directed towards the convicts and slaves of the galleys in Livorno and Civitavecchia between the 16th and 18th centuries. In particular, it analyses and questions the role and tasks of a figure often neglected by historiography: the galley doctor, who was responsible not only for the health of the crew but also for maintaining order and discipline. The project also aims to show how a «culture of vigilance» was an integral, albeit ambiguous, part of early modern European medical theory and practice at all levels. To explore these aspects, the analysis considers the functions and tasks of medical practitioners dealing with galley convicts and slaves in general; focusing in particular on the context of trials of galley slaves accused of suspicious and deviant behavior, such as rioting, simulating illness, and sodomy.